Updates on Interstellar Comet 3I/ATLAS: NASA Images, Many Tails, and Non-gravitational Forces NEW
Sky & Telescope | November 20, 2025
Read article →3I/ATLAS is the third confirmed interstellar object to pass through our Solar System, discovered on July 1, 2025, by the NASA-funded ATLAS telescope in Río Hurtado, Chile. This ancient visitor from beyond our solar system offers scientists a rare opportunity to study material from another star system. [NASA]
Real-time data visualization and comparative analysis of 3I/ATLAS with other celestial objects
Solar flux (W/m²) drives sublimation and activity (Inverse Square Law)
Speed changes due to gravitational acceleration near the Sun (Kepler's Laws)
Gas cloud expansion driven by sublimation
Energy exchange in hyperbolic orbit
Visualizing how solar heating affects 3I/ATLAS's surface temperature and activity as it approaches perihelion
Temperature estimates based on blackbody radiation model. Actual surface temperature may vary based on albedo, composition, and rotation.
Gas production calculated using sublimation physics. CO₂ dominates at large distances (sublimates at 20K), while H₂O requires higher temperatures (170K) and peaks near perihelion. Production scales with solar flux (∝ 1/r²⁻³).
(-118°C / -180°F)
Low activity, minimal sublimation(-35°C / -31°F)
Peak activity, maximum sublimationWater ice actively sublimates
Distance: 1.36 - 2.3 AU from SunCO₂ to H₂O production
One of highest ratios ever observedDetailed physics-based analysis of 3I/ATLAS using orbital mechanics, thermodynamics, and observational astronomy.
Energy exchange between kinetic (KE = ½v²) and potential (PE = -GM/r) during hyperbolic trajectory. Total energy remains constant.
Vector decomposition of velocity: v_r (radial, toward/away from Sun) and v_θ (tangential, perpendicular to radius).
Orbital position angle (θ) measured from perihelion. θ = 0° at closest approach to Sun.
Specific angular momentum L = r × v remains constant throughout orbit (Kepler's second law).
Planck curves showing thermal emission spectrum B(λ,T) at discovery (155K) and perihelion (238K). Peak shifts to shorter wavelengths as temperature increases.
Power-law relationship: Rate ∝ r^(-n) where n depends on sublimation temperature. CO₂ sublimates at 20K, H₂O requires 170K.
Temperature variation across nucleus surface. Peak at subsolar point (noon), minimum on night side. Cosine distribution due to solar illumination angle.
Production rates Q (molecules/s) for CO₂, H₂O, CO, and CN. CO₂ dominates at large distances due to low sublimation temperature.
Gas distribution in coma: N(r) = Q/(4πr²v_exp). Density decreases as r^(-2) for spherical outflow.
Angular size θ = 2×arctan(D/2Δ) for planning telescope resolution requirements. Nucleus ~20 km, coma ~40,000 km.
SNR ∝ D²×10^(-0.4m)×√t for 1-hour exposure. Larger apertures provide quadratically better SNR.
Dynamic pressure P = ρv² shapes ion tail. Solar wind density n ≈ 5/r² cm⁻³, velocity v ≈ 400 km/s.
UV photons dissociate H₂O → OH + H (observed by Swift). Lyman-α (121.6 nm), UV-C, and UV-B components scale as r^(-2).
All charts use physics-based calculations with verified formulas: Kepler's laws, vis-viva equation, blackbody radiation (Planck's law), sublimation physics, and observational astronomy principles. Data sources: mission-constants.js (orbital parameters), JWST observations (composition), Gran Telescopio Canarias (rotation period).
Real-time 2D view of 3I/ATLAS's hyperbolic trajectory through our solar system (view from above)
Note: This visualization is an approximation for educational purposes only. Distances, sizes, and orbital paths are not to scale and are simplified for clarity.
Track the current position of 3I/ATLAS in real-time using official NASA/JPL data and interactive 3D visualizations.
Official NASA orbit visualization tool showing 3I/ATLAS trajectory through the solar system.
Launch NASA Orbit Viewer Note: Search for "3I" or "C/2025 N1" in the small body fieldInteractive 3D solar system view with real-time position data from JPL Horizons.
Open 3D Tracker Real-time updates using official ephemeris dataCurrent coordinates, distance, and speed from TheSkyLive's real-time tracker.
View Live Data Updated using JPL Horizons ephemeris serviceName Breakdown: "3" indicates it's the third known interstellar object, "I" means interstellar, and "ATLAS" refers to the Asteroid Terrestrial-impact Last Alert System discovery telescope. [NASA]
3I/ATLAS likely originated from the Milky Way's galactic thick disk during the "cosmic noon" period of intense star formation 9-13 billion years ago - potentially older than our Solar System itself. Scientists cannot trace it back to its original parent star, adding to its mystery. [arXiv]
July 21, 2025
Captured images showing teardrop-shaped dust cocoon when comet was 277 million miles from Earth. Revealed clear activity with dust emission from Sun-facing side.
August 6, 2025
Near-Infrared Spectrograph observations revealed exceptional CO₂/H₂O ratio of 8:1 - one of the highest ever observed in any comet. Also detected water ice, water vapor, CO, and carbonyl sulfide.
August 7-15, 2025
Detected carbon dioxide gas in coma and found water ice in the nucleus.
2025
10.4m telescope determined rotation period of 16.79 ± 0.23 hours. Physical characterization supports that extrasolar debris is similar to Solar System debris.
Ongoing
Observations showing increasing activity and lengthening tail as it travels through Solar System.
October 2025
ExoMars TGO (CaSSIS camera) and Mars Express captured images during Mars close approach on October 3, 2025.
November 2025
Post-perihelion images by Gianluca Masi showing tail development after emerging from the other side of the Sun.
Peer-reviewed research papers and arXiv preprints about 3I/ATLAS. This collection includes discovery papers, spectroscopic analyses, and theoretical studies from the global astronomical community.
Note on arXiv Papers: arXiv is a preprint repository where scientists share research before peer review. While not yet formally peer-reviewed, these papers represent cutting-edge research by leading astronomers and undergo community scrutiny. Many will eventually appear in peer-reviewed journals.
Sky & Telescope | November 20, 2025
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Read article →Avi Loeb / Medium | NEW
Read article →Avi Loeb / Medium | NEW
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Read article →All real-time orbital data and statistics displayed on this website are calculated using official data from:
Data Update Frequency: Real-time statistics are recalculated every 5 minutes based on current date/time and latest orbital elements. Historical uptime of data sources exceeds 99.9%.
Observations from space telescopes and Mars orbiters capturing 3I/ATLAS's journey through our solar system
Images courtesy of NASA, ESA, NOIRLab, and participating observatories. Click images to view full resolution. All observations show 3I/ATLAS at different stages of its journey through the inner solar system.
Scientific presentations, observations, and educational content about 3I/ATLAS
NASA officials present the latest images and scientific findings about 3I/ATLAS. Features presentations by NASA Associate Administrator Amit Kshatriya, Nicky Fox (Science Mission Directorate), Shawn Domagal-Goldman (Astrophysics Division), and Tom Statler (Lead Scientist for Solar System Small Bodies).
Videos from NASA, ESA, and educational institutions. Click to watch on YouTube.
First interstellar object detected with water by NASA's Swift telescope
Third confirmed interstellar object ever discovered (after 1I/ʻOumuamua and 2I/Borisov)
3I/ATLAS (C/2025 N1) is the third confirmed interstellar object to pass through our Solar System. It was discovered on July 1, 2025, by the NASA-funded ATLAS telescope in Chile. The '3I' designation indicates it's the third interstellar object, 'ATLAS' refers to the discovering telescope.
No, 3I/ATLAS poses no threat to Earth. Its closest approach to Earth will be approximately 1.8 AU (about 270 million kilometers or 168 million miles) on December 19, 2025. For context, 1 AU is the distance from Earth to the Sun, so 3I/ATLAS will be nearly twice that distance away at its closest point. Its trajectory is well-understood and monitored by NASA.
3I/ATLAS requires a telescope to observe. During its brightest period (around perihelion in late October 2025), it reaches a visual magnitude of approximately 9.5-10, which requires at least a 6-8 inch (150-200mm) telescope under dark skies. Binoculars are not sufficient. The comet appears as a faint, fuzzy patch rather than a dramatic sight. Check the Live Tracking section for current sky position.
3I/ATLAS was discovered by the ATLAS (Asteroid Terrestrial-impact Last Alert System) telescope network in Río Hurtado, Chile on July 1, 2025. ATLAS is a NASA-funded early warning system designed to detect near-Earth objects. After the initial detection, astronomers calculated its orbit and confirmed its hyperbolic trajectory with an eccentricity of 6.14, proving it originated from outside our Solar System.
3I/ATLAS is extraordinary for several reasons:
The peak observation window is around perihelion (October 29, 2025) when 3I/ATLAS is brightest at magnitude ~9.5-10. However, it remains visible with telescopes for several months before and after perihelion. The comet is best observed from the Southern Hemisphere initially, but becomes visible from Northern Hemisphere locations as it moves through the solar system. Use the Live Tracking tools to find its current position in the sky.
3I/ATLAS exhibits several anomalous behaviors that make it a unique target for scientific study:
Scientific Significance: These anomalies make 3I/ATLAS an exceptional laboratory for studying interstellar material and comparing planetary system formation across different stars. The non-gravitational acceleration, in particular, is being closely analyzed by researchers including Harvard's Avi Loeb to understand whether it represents purely natural cometary outgassing or hints at more exotic physics.
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